Epidemiologic studies have identified environmental factors associated with an increase in cancer risk. However, for many of these factors, the risk to those exposed is not uniformly distributed. Molecular genetic analysis is becoming an important tool to identify host factors which predisposes to cancer development. The goal of such genetic analysis is to use such information for individual risk assessment and population screening. The focus of this proposal is in identifying genetic factors associated with the development of smoking-related lung cancer. A case control design will be employed. This research will serve as a point for expansion into intervention programs for those found to be at increased risk. The research will also be expanded into other areas including other types of cancer which may have similar mechanisms of initiation. Through my clinical training and experience I have seen that we have little to offer patients after the diagnosis of cancer has been made. We, therefore, need to change the focus of oncology and related fields to prevention. I believe the proposal which I have outlined will be of great value in determining genetic susceptibility and using such information in prevention programs.